Because it's interesting and because it's the day after Halloween. The fundamentalist version of Satan and the role of Satan in society is one of a scheming military adversary, always on the look out to take over and always eager to possess the minds and souls of vulnerable people. He is thought to be something so evil that there need to be exorcisms, prayer defences, prayer meetings, and entire church services devoted to keeping him at bay. Fundamentalists often have a siege mentality regarding the devil and read in this sort of dualistic belief, one side completely good one side completely evil, to the meaning of current events. This has been true for a long time, for instance Bible prophecy shows on TV have been analyzing the news and figuring out just how things happening in the world figure into the devil's wily plan for a while. 9/11 has been integrated into the scheme in due course. But the role they cast for the devil is not exactly what mainstream Christianity, including Catholicism and Orthodoxy, both of which certainly believe in the devil, conceive of him as being.
The easiest way to show this is by looking at what it is the devil does. The traditional notion is that the devil tempts people to sin, leading them to and through temptation and on into sin. But why? What exactly happens to people after they indulge in sin, at the end of their lives? They get thrown into a lifetime of eternal torment in the pit of Hell, tortured by the same devil. Interesting. So the devil tempts people, but the end product of the temptation is the opposite of what the tempting act promises, and that punishment, which is in accord with God's law, is overseen by the devil. It looks like the devil is then doing God's work.
The devil in traditional Christianity is seen more as what the story of Job indicates: a sort of minion, originally on God's side, who tests people's good nature by providing a sort of counterweight, a kind of force tending towards evil to balance out God's force tending towards good. But ultimately this figures into God's plan because in the end it turns out that the promises of the tendency of evil in this world are illusory and that in the afterlife justice is rendered, with the Devil rendering God's Justice to people who have sinned and God rewarding people who have resisted sin and sought to do good.
What this indicates is a relationship between God and Devil closer to the one portrayed in the beginning of "Faust", a collegial relationship between two adversaries who nevertheless have a gentleman's agreement about what the essential nature of the world actually is.
The fundamentalist are wrong because they forget to see the idea that's blithely repeated over and over but that has a great deal of truth for Christian theology, that the existence of the Devil is part of God's plan as well.